Clearly, the blood flow at A, which has already dried and is fading, travels in a vertical direction as if Sheila was upright and maybe twisted or off balance at the time she received this shot. Whereas, the blood flow at B is more horizontal in appearance and appears to still have oxygen in the blood which was a shot inflicted when she was still very much alive, but laying down...
One (flow A) which is vertical in orientation and without oxygen, the other (flow B) horizontal in nature still with oxygen in the blood...